Magnetic Structure of Magnetite Phase of Iron Sand Retrieved from Banten, Indonesia

Among the many types of natural resources that are abundant in Indonesia is iron sand. One of the products of the iron sand processing is magnetite (Fe₃O₄). The stages of separation and purification process that has been done before were extracting magnetite phase and discarding the other phases. Magnetic structure of magnetite phase of iron sand retrieved from Banten, Indonesia has been invesigated. The aims of this research is to analyze the structure of the new magnetite phase, Fe_xM_yO₄. The magnetic properties of the sample was evaluated by means of vibrating sample magnetometer (VSM). Sample characterizations was carried out by neutron activation analysis (NAA) method. The analysis result from NAA shows that there are still 17 impurities remaining, namely: M = Ti, Al, Ce, Co, Cr, Eu, La, Mg, Mn, Na, Sc, Sm, Th, V, Yb and Zn, and there are about 94% of iron sites are filled by Fe elements. The structural analysis was carried out by the help of the high resolution neutron powder diffractometer (HRPD) using a wavelength of λ = 1.8223 Å. Neutron diffraction data was analyzed by means of FullProf software. The analysis result shows that the sample hasthe chemical formula: (Fe0.97M0.03)3O4 with a cubic crystal system, space group: Fd-3m and lattice parameters: a = b = c = 8.36834 (3) Å, α = β = γ = 90°. The sample is magnetic at room temperature because the compound has a net magnetic moment, μ = 2.9(1) μB. The magnetic moments of the sample is lower than the magnetic moments of pure Fe3O4 (μ = 3.8 μB), because of about 3% of Fe sites are occupied by impurity elements. Magnetic properties of magnetite phase depend on the purity of the magnetite phase. (paper)